Process for continuously forming a uniform layer of loose material and installation for carrying out the process

ABSTRACT

A process and apparatus for the continuous production of a uniform layer ofoose material on a forming belt has a receiving belt onto which the loose product is deposited by a gravity chute in strips transverse to a travel direction of the receiving belt. A smoothing device above the receiving belt engages the strip layer over the entire length thereof on the receiving belt and smooths the material before it passes to a dispersing device directly or via said dispersion belt.

CROSS REFERENCE TO RELATED APPLICATION

This application is a national phase application of PCT/EP92/01870 filed17 Aug. 1992 and based upon German national application P41 28 636.7 of29 Aug. 1991 under the International Convention.

FIELD OF THE INVENTION

The invention relates to an apparatus and process for forming a uniformlayer of loose material.

BACKGROUND OF THE INVENTION

In the production of building boards frequently a spreading process,i.e. a dry or quasi-dry manufacturing process, is used. A mixture ofbinders, reinforcement materials and fillers is spread on a movingforming belt and subsequently densified in a press. As is for instanceknown from DE-OS 34 39 493, the layer can be built up by several layersspread onto the forming conveyor belt.

In the DE-OS 37 19 129 a process for the continuous formation of auniform layer of loose material as well as an installation for carryingout the process are described. The continuously incoming loose materialis deposited in strips by means of a gravity chute oscillating acrossthe receiving belt. The deposition period and the speed of the receivingbelt are attuned to each other, so that one strip comes to lie next tothe other, forming a gap-free coating of the receiving belt. In additionto this adjustment, the translatory speed of the gravity chute can befinely varied, in order to systematically even out the height variationsof the deposited layer occurring over the width of the spread layer.

For this purpose the thickness of the spread layer is measured and theresults are used for setting the speed profile of the oscillatinggravity chute. In this way the naturally established mass profile can becounteracted.

In a further development a stripper roll designed as a spiked roller isarranged above the receiving belt, and driven in a direction of rotationselected so that it throws the projecting material in the traveldirection of the receiving belt. This step is particularly importantwhen quick-setting, wetted, gypsum-containing masses are supposed to bespread.

In this process height variations of the plate of 5 to 10% still occur.Such height variations occur especially in wider plates with a width ofapproximately 2.50 m. For the correspondingly larger widths, the heightof the gravity chute is also increased as necessary. Thereby the streamof falling loose material reaches a considerable speed and kineticenergy, which result in uncontrollable movements of the spread materialupon impact on the receiving belt. In this way a gap-free covering ofthe belt is not insured. A rather wavy layer which can even have holesis formed.

Under these conditions the spiked rollers are not in a position to levelthe irregularities, when they work in the travel direction. In practicalapplications it has been found that a uniformization is possible only inthe conventional manner, when the spiked rollers work in the oppositedirection and strip back the projecting material.

This procedure has considerable disadvantages when wet,gypsum-containing mixtures are spread. The reason is that behind theroller accumulations of material are formed which rotate, and in thecore of which material can be caught for periods of minutes.

OBJECT OF THE INVENTION

It is the object of the invention to provide a process and apparatus forthe continuous formation of a uniform layer of loose material which makepossible a better uniformization of the dispersed layer and which aretherefore also suited for larger spreading widths.

SUMMARY OF THE INVENTION

According to the invention the incoming loose material is transformedinto at least one stream of intermediate product, each stream ofintermediate product being deposited in strips on a receiving belttransversely with respect to its travel direction, subjected to thesmoothing action of a combing device working in the travel direction ofthe belt and spread by means of a dispersion device onto a forming belt.Each stream of intermediate product is smoothed by the coming deviceover a combing surface extending in the travel direction of thereceiving belt, whereby the effective length of the combing surface isat least seven times greater than the distance between two strips andthe distance of the combing surface to the receiving belt can be set ata value which is slightly lower than the average height of the layerformed by the strips and which decreases slightly in the traveldirection of the receiving belt.

The apparatus for carrying out the process comprises a belt for theincoming loose material, optionally with a distribution device, and feedbelts, with at least one gravity chute, one receiving belt, one combingdevice and one dispersion device. The gravity chute and the combingdevice are arranged above the receiving belt in succession in the traveldirection of the intermediate product stream and a forming belt isarranged beneath the dispersion device or devices.

The combing device has one or more movable carriers extending in thetravel direction of the receiving belt equipped with combing tools,whereby the carriers are arranged so that they are height-adjustable andthat their angle can be adjusted in the travel direction of thereceiving belt.

The respective stream of intermediate product is smoothed with thecombing device over a combing surface extending in its travel direction.Due to the surface combing it is possible to obtain a substantiallyimproved uniformization of the loose material deposited in strips thanis possible with a spiked roller.

An effective length of the combing surface of at least 7 times thedistance between two strips should be maintained. The effective lengthis smaller than the length of the combing surface by the differencebetween the speed of the combing tools in the travel direction of thereceiving belt and the speed of the receiving belt, in relation to thespeed of the combing tools. In order not to increase too much the lengthof the combing surface, the speed of the combing tools should be amultiple of the receiving belt speed, preferably at least 8 times.

A further improvement of the layer uniformity downstream between thecombing device is obtained when the distance of the combing surface andthe receiving belt is set to a value which lies slightly below theaverage height of the layer formed by the strips.

A slight decrease of the distance between the combing surface and thereceiving belt in the travel direction of the latter contributesadditionally to the uniformization of the layer.

A particularly good uniformization is obtained when the distance betweenthe combing surface and the receiving belt decreases in the traveldirection of the receiving belt to 70 to 98% of the average layer heightand/or by a value between 0 and 3%.

The uniformization is so good that even gaps which occur in largedispersion widths can be evened out. Also periodically forming rises anddepressions in the travel direction, which occur due to overlappingstrips when the deposition is not precisely adjusted, can be evened out.

Downstream of the combing device a layer with uniform thickness over theentire width is obtained.

Advantageously, the stream of intermediate product is deposited on adispersion belt after smoothing and prior to dispersion. The depositionon an additional dispersion belt, for instance by means of a dischargeroller, makes possible a simple adjustment to changes in the speed ofthe forming belt, by changing the speed of the dispersion belt, withouthaving to change the speed of the receiving belt. Besides throughvariations of the dispersion belt speed it is possible to set theoptimal height of the smoothed layer before it reaches the dispersionmachine.

Measuring the mass profile on the dispersion belt is simpler to performthan a measurement taken in or directly downstream of the dispersiondevice, whose surrounding area is always covered by a thick dust. Italso avoids the allowance for thickness defects produced duringpressing, which is considered in a measurement of the finished plate.

The mass profile of the material, which contains water, can be measuredby measuring the water mass. This is particularly well suited forprewetted loose materials, in which the wetness is basically of an evendistribution and thereby proportional to the total mass.

The combing tools are for instance cams, pins, paddles or cleats.

At a length of the receiving belt equal to 8 to 15 times the loweropening of the gravity chute and with carriers extending over the entirefree length of the receiving belt, a speed of the carriers or thecombing tools of about 8 times higher is sufficient for carrying out theprocess.

The combing device can have a band with combing tools passing over tworollers of adjustable individual heights. The combing device can beproduced with little expense.

A drive for moving the carriers, i.e. the plates or frames, are at acertain distance from the layer to be smoothed and thereby less exposedto contamination by whirled-up loose material.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become morereadily apparent from the following description, reference being made tothe accompanying drawing in which:

FIG. 1 is a diagram illustrating an apparatus for producing a layer ofloose material in accordance with the prior art;

FIG. 2 is a view similar to FIG. 1 showing an apparatus for carrying outthe process of the invention in accordance with one example; and

FIG. 3 is a view similar to FIG. 1 of an apparatus for carrying out themethod of the invention in accordance with another example.

SPECIFIC DESCRIPTION

The device shown in FIG. 1 has a mixer 1 whose outlet leads to a belt 2.The belt 2 leads to a distribution device 3. Starting from thedistribution device 3 two feeding belts 4 lead to two gravity chutes 5.Each gravity chute is swingable about an axis 6 arranged in its upperarea.

Further FIG. 1 shows several strips 7 of loose material deposited insuccession on the receiving belt 8, arranged underneath the opening ofthe respective gravity chute 5. Besides the device also has a stripperroll 9 arranged above the receiving belt 8, for smoothing the layer 10,a discharge roller 11 and a dispersion device, basically consisting of adispersion head 12.

The dispersion layer 13 forms on a forming belt 14 running underneaththe two dispersion devices arranged one after the other. The formingbelt 14 runs to a press 15 and a measuring device 16 arranged downstreamthereof.

Besides in FIG. 2 also motors 17 for the swinging motion of the gravitychutes 5 are shown.

In operation the loose material mixed in mixer 1 is conveyed on belt 2to the distribution device 3, which supplies two feeding belts 4 to thegravity chute 5. The gravity chutes 5 swing about axis 6 to, wherebythey deposit strips 7 of the loose material onto the receiving belt 8.The stripping roller 9 combs the surface of the layer against theconveying direction. From DE-OS 37 19 129 also a spiked roller combingin the conveying direction, i.e. the travel direction of the receivingbelt 8, is known. The discharge brush 11 throws the material to bedispersed onto the actual dispersion head 12. The final dispersed layeris created on the forming belt 14 through the dispersion heads arrangedin succession. Downstream of press 15 the thickness or a thickness anddensity profile is measured by a measuring device 16. The results ofthis measurement are processed for the control of drives 17 of thegravity chutes 5.

EXAMPLE 1

In the first example (FIG. 2) a device according to the inventiondistinguishes itself over the prior art in the following manner:

The device has a substantially longer receiving belt 8a. The length ofthe receiving belt 8a starting from the gravity chute 5 is approximately8 times greater than the bottom opening of the gravity chute 5, i.e.eight strips 7 can be deposited.

It has a combing device with a carrier, here a band with cams 18, guidedaround two rollers. The combing device extends from the gravity chute 5over the entire length of the receiving belt 8a.

The band 18 extends of course also over the entire width of thereceiving belt 8a.

The rollers supporting the band are each mounted to be height-adjustableon a frame not shown in the drawing. As a result the combing surfaceresting on the surface of the layer is height-adjustable in itsentirety, as indicated by arrow 19, and, as indicated by an angle symbol20, its angle can also be adjusted.

The combing surface is thereby arranged so that its distance to thereceiving belt 8a decreases in the travel direction of the receivingbelt 8a at an angle between 0° and 3°, here 2°.

At the end of the receiving belt 8a, an additional discharge roller 21is provided. The discharge roller is larger than discharge roller 11upstream of the dispersion device (FIG. 1).

Also additionally underneath the discharge roller 21 a dispersion belt8b is arranged. At its end there is the discharge roller 11 and thedispersion device with the dispersion head 12.

A two-part measuring device 22 is arranged at the dispersion belt 8b,underneath and above the smoothed layer. The second upper part of themeasuring device 22 can also be arranged above an empty belt portion ofthe receiving belt 8a which runs above the dispersion belt 8b, in orderto avoid contamination (in FIG. 2 shown in broken lines).

For cleaning purposes the dispersion belt 8b is guided over a roller 23,closely above the forming belt 14, outside the dispersed layer. This isparticularly advantageous in the case of wet, gypsum containingmixtures.

Like in the state of the art, the receiving belt 8a and the forming belt14 have the same width. The dispersion belt 8b has also the same width.

In operation the stream of intermediate product supplied through thefall chute 5 is deposited in strips on the receiving belt 8a. The formeduneven layer in this case of eight adjacent strips 7 is combed over theentire accessible area of the receiving belt by the combing device whichacts on the whole surface of the stream of semi-finished product in thedirection in which it is conveyed.

Thereby the travel speed of the cams 18 is a multiple, here 10 times, ofthe speed of the receiving belt 8a. The higher the speed of cams 18,i.e. of the comb tools, the bigger the effective length of the combing.

The effective length of the combing surface is here approximately 7times the distance between two strips 7 (more accurately 7.2 times). Thedistance of cams 18 to the receiving belt 8a is set here at 98% of theaverage height of the layer and decreases in the travel direction of thereceiving belt 8a by 2%.

Due to the slightly decreasing distance of the combing surface to thereceiving belt 8a, the deposited layer is lightly pressed togetherduring combing. A smoothed layer of even height is created. Due to arelatively low speed of the receiving belt 8a, a layer with a biggerheight than the height upstream of the dispersion device is created andthereby higher than the layer produced by the state of the artdownstream of stripping roller 9. A low receiving belt speed also makespossible a favorable, i.e. high speed ratio between the combing deviceand the receiving belt.

At the end of receiving belt 8a the loose material is thrown by means ofdischarge roller 21, whose size corresponds to the height of the layer,onto the dispersion belt 8b, which has a higher speed than the receivingbelt 8a. On the dispersion belt 8b a considerably more even layer iscreated than the one formed solely by deposition downstream of thegravity chute 5.

On the dispersion belt the mass profile is measured across thedispersion width by means of measuring device 22.

The measuring device 22 can determine the mass with radioactive isotopes(gamma rays absorption) the measuring device 22 can alternatively be adevice for mechanically weighing this mass. In the case of wet mixes, ameasuring device 22 for measuring the mass of water, for instance bymicrowave steaming is used. By measuring the mass profile of eachindividual stream of intermediate product on the respective dispersionbelt 8b and by feedback to the drive 17 of the gravity chute 5 themovement of the single gravity chute 5 can be individually adjusted viasmall variations in its translatory speed.

Instead of a band with cams 18 it is also possible to use an arrangementof chains with cams or pins, guided along each other. Instead of thepin-shaped combing tools, it is also possible to use wider tools, suchas paddles and cleats. In the case of paddles, these can also bearranged alternately inclined, this way achieving in addition a limitedlateral uniformization.

Besides, the band or the rollers can be provided with a heating devicein order to prevent condensation. In operation the band with the combingtools is heated to a temperature above the dewpoint existing in thesurroundings of the receiving belt 8a.

EXAMPLE 2

The installation of Example 3 (FIG. 3) differs from the one of Example 1in that it has another embodiment of the combing device.

The combing device of Example 3 has several vertical plates 24a, 24barranged in the travel direction of the receiving belt 8a, eacheccentrically suspended in the front and the back on a crankshaft 25,whereby the plates 24a, 24b are located in slots of the crankshafts 25.

The crankshafts 25 are arranged parallel to one another and aresynchronized, i.e. have for instance a common drive.

On their edges oriented towards the receiving belt 8a, the plates 24a,24b have teeth or other combing tools. In operation these combing toolsperform circular motions indicated by the circle symbol 26 and therebyact as a plurality of interengaging spike rollers.

The crankshafts 25 are individually height-adjustable, so that the totalheight (arrow 19), as well as the angle (arrow 20) of the combingsurface represented by the effective line 27 can be adjusted. Theabove-mentioned circular motions are performed along the effective line27.

The plates 24a, 24b are guided in guides 28 arranged approximately attheir half height and having slots running parallelly to the traveldirection of receiving belt 8a. These guides 28 prevent an uncontrolledlateral swinging.

In addition a device for controlling the lateral oscillations of thecrankshafts 25 and/or the guides 28 can be provided. In this way animproved coverage of the layer can be achieved.

It is also possible to use frames instead of plates 24a, 24b.

The propulsion by means of crankshafts is only an example of severalpossibilities to achieve alternating motions of the combing tools.Especially the circular motion, circle symbol 26, can be replaced byelliptical motions or by linear motions along the effective line 27. Itis also within the framework of the invention to arrange the combingtools transversely to the conveying direction so that they interengageand comb alternately.

The advantage of this embodiment is that problems such as contaminationby dust and condensation in the case of wet and warm loose material canbe controlled. All surfaces with a horizontal component are avoided andthe drive is kept away from the dust zone.

The plates 24a, 24b or frames can be additionally provided with heatingdevices to prevent condensation. By heating the plates 24a, 24b it isnot necessary to heat any rotating parts.

The way the invention works was calculated in a computer simulation. Thecalculation starts with the simplified assumption that the layerdeposited through the gravity chute 4 has a base height of 3 cm and thaton top of that lies a sinusoidal wave with an amplitude of 6 cm, so thatan average height of 6 cm results.

The effective length (Table 1, line 1) is indicated to be a multiple ofthe distance between strips 7. The distance between strips 7 correspondsin the case of adjacently disposed strips 7 to the width of thedeposited strips 7. The results of the simulation are given in Table 1.

In the first block of the table the height of the lowest point of thecombing band above the receiving belt is varied. It can be seen that thebest effect is obtained closely below the average height of thedeposited layer. The effect stabilizes at good values for the lowerheights. When the height is greater than the average layer height, theefficiency decreases dramatically and here and there holes appear in thelayer deposited on dispersion belt 8b.

The second block varies the effective length. It can be seen that theefficiency decreases below ten times the distance between strips 7.

Therefore a particularly good uniformization is achieved when theeffective length is 10 to 15 times the distance between the strips 7.

However also at an effective length of 7 to 9 times the distance betweenstrips 7 considerably lower height variations are achieved than with thestate of the art.

The third block of the table varies the setting angle of the combingsurface; the angle is here indicated in % of gradient. It has been foundthat negative angles are of little help and that above 2.5% theefficiency decreases quickly.

In further calculations it has been found that the measure by which thedeposited layer varies has only a slight influence on the result, aslong as the other parameters are maintained as established above.

The strips 7 must no longer be precisely laid out one next to the otherduring their deposition through the gravity chute 4. For instance smalloverlappings of strips 7 do not contribute to height variations orcontribute very little to height variations.

Example: The gravity chute oscillates with a medium cycle time of 6 s.The average width of the deposited strips is 30 cm, the average heightequals 6 cm, the variation is ±3 cm. The length of the receiving beltafter the point where it is impacted by the loose material is 3.5 m, thelength of the combing device 3.3 m. The speed of the receiving beltequals 3.0 m/min, the speed of the combing device 30 m/min. The heightof the lowermost attack point of the effective line of the cams lies at5 cm above the receiving belt. With this selection also the differencesin the transverse distribution up to 15% are covered. The setting angleis 1%. This way an excellent uniformization of the layer deposited onthe dispersion belt 8b is achieved and it is also insured that loosematerial does not dwell longer on the receiving belt 8a than it issuitable to the belt speed.

The speed of the dispersion belt 8b is 6 m/min and correspondingly theheight of the layer on the belt is 30 mm. At a bulk weight ofapproximately 250 kg/m³ a surface load of 7.5 kg/m² results.

If a surface weight of the dispersion belt 8b of 750 g/m² and avariation range of ±5% are assumed, the measuring error induced by thebelt in a mass measurement is ±0.5% at the dispersion belt 8b.

                                      TABLE 1                                     __________________________________________________________________________    COMPUTER SIMULATION OF A COMBING DEVICE                                       __________________________________________________________________________    Column          1   2  3   4   5   6   7   8   9   10                         __________________________________________________________________________    Effective length                                                                              10                                                            Amplitude variation                                                                        cm 6.0                                                           Base height  cm 3.0                                                           Average height strip                                                                       cm 6.0                                                           Maximum height strip                                                                       cm 9.0                                                           Minimum height strip                                                                       cm 3.0                                                           Standard variation                                                                         %  35.5                                                          End height comb                                                                            cm 5.0 5.5                                                                              5.8 5.85                                                                              5.9 5.95                                                                              6.0 6.2 6.5 7.0                        Gradient comb                                                                              %  2.0                                                           Average height result                                                                      cm 6.0 6.0                                                                              6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0                        Maximum height result                                                                      cm 6.3 6.3                                                                              6.24                                                                              6.08                                                                              6.08                                                                              6.1 6.2 6.4 6.6 7.1                        Minimum height result                                                                      cm 5.9 5.9                                                                              5.90                                                                              5.92                                                                              5.92                                                                              5.5 5.1 4.1 3.6 3.0                        Standard variation                                                                         %  1.3 1.3                                                                              1.1 0.9 0.85                                                                              2.5 3.9 10.6                                                                              16.4                                                                              24.9                       Maximal variation                                                                          %  6.2 6.2                                                                              5.7 2.7 2.7 9.8 17.0                                                                              36.6                                                                              51.1                                                                              68.7                       __________________________________________________________________________    Column          11     12 13     14 15      16 17                             __________________________________________________________________________    Effective length                                                                              20     15 10     8  7       5  3                              Amplitude variation                                                                        cm 6.0                                                           Base height  cm 3.0                                                           Average height strip                                                                       cm 6.0                                                           Maximum height strip                                                                       cm 9.0                                                           Minimum height strip                                                                       cm 3.0                                                           Standard variation                                                                         %  3.5                                                           End height comb                                                                            cm 5.9                                                           Gradient comb                                                                              %  2.0                                                           Average height result                                                                      cm 6.0    6.0                                                                              6.0    6.0                                                                              6.0     6.0                                                                              6.0                            Maximum height result                                                                      cm 6.08   6.08                                                                             6.08   6.1                                                                              6.2     6.3                                                                              6.4                            Minimum height result                                                                      cm 5.94   5.93                                                                             5.92   5.7                                                                              5.5     4.7                                                                              4.1                            Standard variation                                                                         %  0.66   0.83                                                                             0.85   1.59                                                                             2.57    5.82                                                                             8.9                            Maximal variation                                                                          %  2.3    2.5                                                                              2.7    7.2                                                                              10.9    26.3                                                                             38.7                           __________________________________________________________________________    Column          18    19  20   21 22   23                                                                              24   25 26                           __________________________________________________________________________    Effective length                                                                              10                                                            Amplitude variation                                                                        cm 6.0                                                           Base height  cm 3.0                                                           Average height strip                                                                       cm 6.0                                                           Maximum height strip                                                                       cm 9.0                                                           Minimum height strip                                                                       cm 3.0                                                           Standard variation                                                                         %  35.5                                                          End height comb                                                                            cm 5.9                                                           Gradient comb                                                                              %  -1.0  -0.5                                                                              0.0  0.5                                                                              1.0  1.5                                                                             2.0  2.5                                                                              3.0                          Average height result                                                                      cm 6.0   6.0 6.0  6.0                                                                              6.0  6.0                                                                             6.0  6.0                                                                              6.0                          Maximum height result                                                                      cm 7.5   7.2 6.8  6.1                                                                              6.1  6.2                                                                             6.1  6.1                                                                              6.4                          Minimum height result                                                                      cm 5.8   5.8 5.9  6.0                                                                              6.0  5.9                                                                             5.9  5.8                                                                              5.4                          Standard variation                                                                         %  7.65  5.8 4.55 0.35                                                                             0.65 0.9                                                                             0.85 1.55                                                                             3.2                          Minimum variation                                                                          %  29.4  22.8                                                                              15.4 1.3                                                                              2.3                                         Maximal variation                                                                          %                         2.8                                                                             2.7  5.9                                                                              16.4                         __________________________________________________________________________

I claim:
 1. A process for the continuous production of a uniform layerof a loose material, comprising the steps of:(a) transforming anincoming loose material into at least one stream of an intermediateproduct; (b) depositing said intermediate product in a layer of stripson a receiving belt transversely with respect to a travel direction ofsaid receiving belt; (c) subjecting said layer of strips of saidintermediate product on said receiving belt to smoothing action of acombing device working in said travel direction and over an effectivelength of a combining surface which is at least 7 times greater than adistance between two successive strips; (d) setting a distance of saidcombing surface from said receiving belt at a value which is slightlyless than an average height of said layer of strips and which decreasesslightly in said travel direction; and (e) dispersing said material fromsaid receiving belt following discharge from an end thereof onto aforming belt to form said uniform layer of said loose material thereon.2. The process defined in claim 1 wherein the distance of the combingsurface from said receiving belt is set at 70 to 98% of said averageheight of said layer of strips.
 3. The process defined in claim 1wherein the distance of the combing surface from said receiving beltdecreases by a value between zero and 3% in said travel direction of thereceiving belt.
 4. The process defined in claim 1 wherein said stream ofsaid intermediate product is deposited from said receiving belt on adispersion belt before being dispersed onto said forming belt.
 5. Theprocess defined in claim 4, further comprising the step of measuring amass profile on said dispersion belt and controlling a deposition speedof said strips in response to the measurement.
 6. The process defined inclaim 5 wherein said mass profile is measured by measuring water mass.7. An apparatus for the continuous production of a uniform layer of aloose material by the steps of:(a) transforming an incoming loosematerial into at least one stream of an intermediate product; (b)depositing said intermediate product in a layer of strips on a receivingbelt transversely with respect to a travel direction of said receivingbelt; (c) subjecting said layer of strips of said intermediate producton said receiving belt to smoothing action of a combing device workingin said travel direction and over an effective length of a combiningsurface which is at least 7 times greater than a distance between twosuccessive strips; (d) setting a distance of said combing surface fromsaid receiving belt at a value which is slightly less than an averageheight of said layer of strips and which decreases slightly in saidtravel direction; and (e) dispersing said material from said receivingbelt following discharge from an end thereof onto a forming belt to formsaid uniform layer of said loose material thereon, said apparatuscomprising: a feed belt for supplying said loose material; another beltforming said receiving belt and located below said feed belt; at leastone gravity chute above said receiving belt and receiving said loosematerial from said feed belt and depositing said loose material on saidreceiving belt; means above said receiving belt forming said combingdevice, said combing device having at least one movable carrierextending in said travel direction and equipped with combing tools, saidcarriers being height adjustable and having an adjustable angle in thetravel direction of the receiving belt; a dispersion device receivingsaid material from said receiving belt; and a further belt below saiddispersion device and constituted as said forming belt.
 8. The apparatusdefined in claim 7 wherein said receiving belt has a length from saidgravity chute to a discharge end thereof between 8 and 15 times a loweropening of the gravity chute and said carriers extend over an entirefree length of the receiving belt.
 9. The apparatus defined in claim 7wherein said combing device has a band with combing tools passing overtwo rollers which are individually height adjustable.
 10. The apparatusdefined in claim 7 wherein said combing device has a plurality of platesor frames arranged vertically in said travel direction and eccentricallysuspended on two individually height-adjustable crank shafts.
 11. Theapparatus defined in claim 7, further comprising a dispersion beltupstream of said dispersion device and following said receiving belt.12. The apparatus defined in claim 7, further comprising a measuringdevice on said dispersion belt for measuring a mass profile thereon.